Lipoprotein analysis by differential charged-particle mobility

Abstract

The invention provides methods of preparation of lipoproteins from a biological sample, including HDL, LDL, Lp(a), IDL, and VLDL, for diagnostic purposes utilizing differential charged particle mobility analysis methods. Further provided are methods for analyzing the size distribution of lipoproteins by differential charged particle mobility, which lipoproteins are prepared by methods of the invention. Further provided are methods for assessing lipid-related health risk, cardiovascular condition, risk of cardiovascular disease, and responsiveness to a therapeutic intervention, which methods utilize lipoprotein size distributions determined by methods of the invention.

What is claimed is: 
     
       1. A method for purifying lipoproteins for differential charged particle mobility analysis, said method comprising:
 a) incubating a solution comprising lipoproteins, non-lipoproteins, dextran sulfate and a solid support comprising a paramagnetic particle, under conditions for said lipoproteins to bind to said solid support; 
 b) isolating said solid support from the solution thereby separating said lipoproteins from said non-lipoproteins; and 
 c) releasing said lipoproteins from said solid support, wherein said released lipoproteins are suitable for differential charged particle mobility analysis that determines size distribution of said lipoproteins; 
 and d) subjecting said lipoproteins to differential charged particle mobility analysis 
 wherein:
 said lipoproteins comprise HDL and one or more selected from the group consisting of LDL, Lp(a), IDL and VLDL; and 
 said method does not include centrifugation. 
 
 
     
     
       2. The method according to  claim 1 , wherein said solid support comprises a bead. 
     
     
       3. The method according to  claim 1 , wherein said solid support comprises a lipoprotein-capture ligand capable of binding lipoproteins. 
     
     
       4. The method according to  claim 3 , wherein said lipoprotein-capture ligand is selected from the group consisting of an aptamer and an antibody. 
     
     
       5. The method according to  claim 1 , wherein subjecting said lipoprotein to differential charged particle mobility analysis comprises:
 determining a differential mobility particle size distribution in one or more regions of particle sizes for said lipoproteins; 
 subtracting contribution to the particle size distribution of a non-lipoprotein reagent or a non-lipoprotein sample material to obtain a lipoprotein particle size distribution; and 
 outputting the lipoprotein particle size distribution to a display, a printer or a memory. 
 
     
     
       6. The method according to  claim 5 , wherein the determining a particle size distribution includes determining a best fit for the one or more regions. 
     
     
       7. The method according to  claim 6  wherein the best fit is of the form:
     y   1   =k   1   *e   (−0.7*d) ; 
 where y 1  is a contribution to the measured differential mobility size distribution, k 1  is an empirical constant of the fit, and d is particle diameter; 
 wherein the determining a best fit includes calculating a value for k 1 . 
 
     
     
       8. The method according to  claim 5 , wherein the subtracting includes applying a theoretical curve representing particle size distribution of the non-lipoprotein reagent or the non-lipoprotein sample material. 
     
     
       9. The method according to  claim 5 , wherein the non-lipoprotein reagent is Reactive Green 19 conjugated with dextran (RGD). 
     
     
       10. The method according to  claim 5 , wherein the non-lipoprotein sample material is albumin. 
     
     
       11. A method for purifying lipoproteins for differential charged particle mobility analysis, said method comprising:
 a) incubating a solution comprising lipoproteins, non-lipoproteins, dextran sulfate and a solid support comprising a paramagnetic particle, under conditions for said lipoproteins to bind to said solid support; 
 b) isolating said solid support from the solution thereby separating said lipoproteins from said non-lipoproteins; 
 c) releasing said lipoproteins from said solid support; 
 d) subjecting said lipoproteins to differential charged particle mobility analysis that comprises:
 determining a differential mobility particle size distribution in one or more regions of particle sizes for said lipoproteins; and 
 subtracting contribution to the particle size distribution of a non-lipoprotein reagent or a non-lipoprotein sample material to obtain a lipoprotein particle size distribution; and 
 outputting the lipoprotein particle size distribution to a display, a printer or a memory; 
 
 wherein:
 said lipoproteins comprise HDL and one or more selected from the group consisting of LDL, Lp(a), IDL and VLDL, and 
 the determining a differential mobility particle size distribution includes determining a best fit for the one or more regions. 
 
 
     
     
       12. The method according to  claim 11 , wherein said method does not include centrifugation. 
     
     
       13. The method according to  claim 11 , wherein said solid support comprises a bead. 
     
     
       14. The method according to  claim 11 , wherein said solid support comprises a lipoprotein-capture ligand capable of binding lipoproteins. 
     
     
       15. The method according to  claim 14 , wherein said lipoprotein-capture ligand is selected from the group consisting of an aptamer and an antibody. 
     
     
       16. The method according to  claim 11  wherein the best fit is of the form:
     y   1   =k   1   *e   (−0.7*d) ; 
 where y 1  is a contribution to the measured differential mobility size distribution, k 1  is an empirical constant of the fit, and d is particle diameter; 
 wherein the determining a best fit includes calculating a value for k 1 . 
 
     
     
       17. The method according to  claim 11 , wherein the subtracting includes applying a theoretical curve representing particle size distribution of the non-lipoprotein reagent or the non-lipoprotein sample material. 
     
     
       18. The method according to  claim 11 , wherein the non-lipoprotein reagent is Reactive Green 19 conjugated with dextran (RGD). 
     
     
       19. The method according to  claim 11 , wherein the non-lipoprotein sample material is albumin.